It is common for a company to purchase a physical server which is utilized in association with their business. However, one of the disadvantages is that only about 5-10% of the capabilities of the physical server may be utilized by that company. As such, the physical server is under-utilized. However, the use of virtual servers is slowly gaining acceptance. For example, instead of ten people buying ten physical servers, ten people can buy one server and split its cost ten ways. As such, each of the ten owners can have their own virtual server software operating on the commonly owned physical server. However, user acceptance of this situation is still inhibited due to concerns over shared server resources not being available during a peak load requirement for any given virtual server.
One conventional solution for providing for virtual server peak loads is to ensure that each host physical server has the resource capacity local to the physical system. As such, the number of virtual servers on any given host is usually limited such that if a majority of virtual servers required additional resources, those resources would normally be available. However, this conventional solution leads to the general under-utilization of the host.
It is understood that if more virtual servers were placed onto their host, the average utilization of the host would increase. However, the additional headroom available for peak capacity would also decrease, limiting the ability for a virtual server to obtain additional resources during peak usage. As more virtual servers are loaded onto a host, the headroom slowly disappears until there is no longer any capacity for peak loads on any given virtual server.
If a host server was loaded to this point and a virtual server experienced the need for additional resources, one of two side-effect conditions typically occurs. For example, if the virtual server experiencing peak usage requirements were a higher priority than other virtual servers on the host, it would obtain its required resource at the expense of the rest of the virtual servers on the host (e.g., which may be limited by user-defined minimums set for all virtual servers). Alternatively, if the virtual server experiencing peak usage requirements were the same priority as the rest, it could be blocked and not be assigned additional resources. Given either side-effect condition, the result is unpredictable and inconsistent performance characteristics for any given virtual server on a host and leads to the perception of resources not being available when they may be required.
The present invention may address one or more of the above issues.